The subject matter of the present invention relates generally to food product defect sensing and removal, and in particular, to food product defect sensing and trimmer apparatus and method which is capable of removing defects of different length at any position on the product without appreciable waste. The food product defect sensing and trimmer apparatus and method of the present invention is especially useful when employed to remove the defects from french fried potato strips, but is also suitable for use in the removal of defects from other elongated food products such as green beans and the like.
Previously, it has been proposed in U.S. Pat. No. 3,382,975 of Hoover issued May 14, 1968 to provide a food product defect sensing and sorting apparatus using a plurality of light sensors surrounding a transparent tube through which the food product is conveyed by water, to detect the defective products which are sorted out by ejecting them from the stream with an air jet deflector. Unlike the present invention, there is no cutter for cutting the defects out of the potato strips or other elongated food products in response to the sensing of such defects by the light detectors.
U.S. Pat. Nos. 4,147,619 and 4,186,836 of Wassmer et al issued Apr. 3, 1979 and Feb. 5, 1980, respectively, show similar apparatus for sensing defects in potatoes by means of light detectors and sorting out the defective potatoes without trimming or cutting out the defects. Wassmer et al U.S. Pat. No. 4,147,619 shows an apparatus for sensing defects in peeled potatoes and sorting out defective potatoes when the number of defects exceeds a predetermined minimum. The sensors are light reflection sensors in the form of self-scan diode array cameras which are spaced about a transparent tube through which the potatoes fall. The defective potatoes are sorted out by air-jets which reject them from the main stream of potatoes. However, there is no cutter for removing the defects and no data processor which determines the length of the food products and the position of a defect on the product as well as the size of the defect in the manner of the present invention.
Wassmer et al U.S. Pat. No. 4,186,836 discloses apparatus for sensing and sorting indiscriminately or randomly mixed food products, such as hash brown potato pieces, by selectively ejecting defective products through suction tubes. The sensing means radiates the top of the potato pieces with visible light and infrared light, which are detected by the same camera containing dual arrays of light detection diodes. U.S. Pat. No. 4,385,700 of Hodges et al issued May 31, 1983 shows a similar defect scanning and sorting apparatus for french fried potato strips. Thus, unlike the present invention, the light is not caused to be reflected off both sides and the top surface of a french fried potato strip or other elongated food product to three pairs of detectors to detect defects as such product is transmitted through separate channels on the conveyor. There is no ratio of the visible light to infrared light signals formed to provide defect recognition. Also, there is no cutter means for each channel which is controlled by the output signal of the sensor means to remove the defects by cutting them out of the food product.
It has also been proposed in U.S. Pat. No. 4,114,488 of Vornfett issued Sept. 19, 1978 to provide an elongated food product defect sensing and trimming apparatus including a cutter having a pair of knife blades supported so that such blades are separated by a fixed spacing. The knife blades are moved downward together to cut the potato strip or other food product while such product is being conveyed through a V-shaped feeder trough or channel. However, this cutter has the disadvantage that it is not capable of changing the space between the two knife blades to cut defects of a different length without appreciable waste. Thus, unlike the present invention, such cutter does not employ a single pivoted knife for making two or more cuts through the potato strip at variable spacings in order to accommodate defects of a different length. Furthermore, the nature of the light sensor used to detect the defects is not disclosed. Thus, the sensor appears to be a conventional visible light detector means in the form of a plurality of photocells positioned above the conveyor troughs or channels which scan the potato strips conveyed through such channels. In addition, there is no teaching of the use of a data processor circuit for determining the length of the potato strip, the position of the defect on the potato strip and the size of the defect. Finally, there is no disclosure of removing the defect with a minimum of waste by adjusting the spacing distance between two cuts of a single knife blade which is pivoted back and forth across the path of the potato strip to cut off defects of different length, in the manner of the present invention.
It has previously been proposed by Kroenig in U.S. Pat. Nos. 4,251,555 and 4,351,232 issued Feb. 17, 1981 and Feb. 28, 1982, respectively, to provide a method and apparatus for sensing defects in potato strips and trimming the ends of the defective strips with a rotating cutter to remove defects, thereafter again sensing and sorting the trimmed strips to make sure that all the defect has been removed. However, unlike the present invention, the sensor is a visible light sensor which scans the potato strips as they fall through a transparent tube surrounded by the light source and detectors. Also, the cutter employs a rotating cutter blade which is only capable of making one cut per potato strip to remove the defects on the ends of such strip. Thus, unlike the present invention, the cutter is not capable of making two or more cuts per strip and cannot vary the spacing between the two cuts to remove defects of different length. As a result, there is much wastage when using the apparatus of Kroenig and it requires a longer time to remove the defects.